Now when I add it under my playlist or Timeline it’s like if it was bugging and not reproduce it using the speed it should. (kindda like if the internet connection was slow and trying to load the video every seconds) Do you know how to fix?
If you are on macOS, this is a known bug that is intermittent. Restarting the app usually fixes it. If you are not on macOS, then I do not know, You can try the different options under Settings > Display Method. If you reply, you need to mention your OS, your Shotcut version, and the Display Method setting,